<header id="header" class="container-fluid">
    <nav  class="navbar   navbar-fixed-top navbar-transparen" role="navigation">
        <div class="container-fluid header_container">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle" data-toggle="collapse"
                        data-target="#example-navbar-collapse">
                    <span class="glyphicon glyphicon-align-justify"></span>
                    <span class="sr-only">切换导航</span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                <a class="navbar-brand" href="/"><span class="glyphicon glyphicon-home"></span> Photo Share</a>
            </div>

            <div class="collapse navbar-collapse navbar-right"  id="example-navbar-collapse">
                <ul class="nav navbar-nav">
                    <li>
                        <a id="login_button" href='/login/0'>
                            <span class="glyphicon glyphicon-user"></span>
                            登录
                        </a>
                    </li>
                    <li>
                        <a id="register_button" href="/user/register">
                            <span class="glyphicon glyphicon-plus"></span>
                            注册
                        </a>
                    </li>
                    <li>
                        <a  href="/DownloadApp">
                            <span class="glyphicon glyphicon-qrcode"></span>
                            下载APP
                        </a>
                    </li>
                    <li>
                        <a href="/visitor">
                            <span class="glyphicon glyphicon-eye-open"></span>
                            游客模式
                        </a>
                    </li>
                    <li>
                        <a target="_blank" href="/task">
                            待办事项
                        </a>
                    </li>
                    <li class="dropdown">
                        <a href="#" class="dropdown-toggle" data-toggle="dropdown">
                            <span class="glyphicon glyphicon-th-large"></span>
                            图片分类  <b class="caret"></b>
                        </a>
                        <ul  class="dropdown-menu" style="text-align: center;">
                            <li><a href="/#page1">热门推荐</a></li>
                            <li><a href="/#page2">风景</a></li>
                            <li><a href="/#page3">美女</a></li>
                            <li><a href="/#page4">往日榜单</a></li>
                            <li><button type="button" class="btn btn-danger navbar-btn hidden"> 退出登录 </button></li>
                        </ul>
                    </li>
                    <li><a href="/readme">联系我们</a></li>
                </ul>
            </div>
        </div>
    </nav>
</header>
